I cant figure out adb

I just cant figure out this whole adb issue. if I type in"adb shell" it pulls up the adb command box, but after that, anything I type in, it says not found.for example, if I type in "adb devices", it says "adb not found". Anyone have any ideas?

Running "adb shell" is not giving you an adb-shell but rather giving you a unix shell on the ADB device. So try unix commands, such as ls (list files) and cd (change directory). And "exit" when you are done with the shell (or just close the window).

If you want to run "adb devices" or similar just run that directly, no need for the shell.